My nrf52840 DK have problem!

[MainOFF]

I have a nrf5280 PDK. I worked well. But now, when i plug micro usb capble from my computer. Led5 do not light or blink. and I can't load my program to nrf52840. How can I repair it?

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I was check my usb capble! Do not have problem!

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when I flash my board by kiel C5 :"no J-Link found"

[MartinBL]

Hi, just a few standard questions for you:

1. Does the device show up in Device Manager on your computer? Please try to connect and disconnect the kit a few times. It might show up with unexpected names.
2. Have you tried a different USB cable? Faulty cables are surprisingly often the issue.
3. Have you tried to press the IF BOOT/RESET button while power cycling the kit? It should then show up as a Removable Storage Device named "BOOTLOADER". Then you can drag-and-drop this file onto the storage device to reprogram the JLINK firmware.
4. Can you measure the supply voltage on the nRF Device?
5. Can you make sure that you are using the latest J-Link driver version? www.segger.com/.../jlink
6. Can you try this guide? devzone.nordicsemi.com/.../

[MainOFF]

I was test all your question! And when I press IF BOOT/RESET button while power cycling the kit. Led5 blink. but can't flash. "No-Jlink found"

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thanks Martin Børs-Lind! I was repair my board after use your help! :) you are so kind!